Modeling of Hydrate Dissociation Curves with a Modified Cubic-Plus-Association Equation of State

Palma, André M.; Queimada, António J.; Coutinho, João A. P.

doi:10.1021/acs.iecr.9b02432

Cited by 6 publications

(8 citation statements)

References 59 publications

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“…The model describes accurately the results of Mohammadi and Richon and Maekawa at lower inhibitor contents, but clearly underpredicts the pressure results for the remaining sets, especially in the water–liquid–hydrate section of the dissociation curve. As presented in a previous study these differences are already significant for the pure hydrate of CO 2 , introducing higher uncertainties for the parametrization of this hydrate. For the remaining compounds in study there appear to be slight underestimations of the hydrate dissociation curves, however, these are within a small range of temperatures and Δ T are mostly below 1 K. Results for the remaining inhibitors in study when applied to the CO 2 hydrate are presented on Table and in the SI.…”

Section: Results and Discussionmentioning

confidence: 64%

“…These are different from those used in previous works, due to the simultaneous fitting to VLE and SLE equilibria. The remaining binary interaction parameters were presented in previous works. ,,,, …”

Section: Results and Discussionmentioning

confidence: 99%

“…The remaining binary interaction parameters were presented in previous works. 4,12,16,19,20 For methanol, ethanol and MEG there was a need to introduce a binary interaction parameter for the volume of association to describe simultaneously SLE and VLE. The value of the volume of association for water is 0.483 × 10 −2 , which is just 1 order of magnitude above the values presented for the binary interaction parameters, which justifies their relevance for the present equilibria calculations.…”

Section: Resultsmentioning

confidence: 99%

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Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Palma

Queimada

Coutinho

2019

Ind. Eng. Chem. Res.

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A modified CPA equation of state has been applied for the description of noninhibited hydrates. In this work, this model is applied to the description of dissociation curves of hydrates inhibited by six thermodynamic inhibitors (methanol, ethanol, MEG, DEG, TEG, and glycerol), while also focusing on promoting a correct simultaneous description of SLE and VLE between the inhibitors and water. The study concern some of the most well-known hydrate formers (methane, ethane, propane, CO 2 , Xe, and H 2 S) and mixtures of these gases. The maximum number of binary interaction parameters applied between water and the hydrate inhibitor is two, one for the physical term and one for association. A comparison between this approach and the hydrates model present on Multiflash is reported, revealing that the present approach, while less accurate than Multiflash is still able to correctly describe hydrate inhibition, VLE and LLE, while using a smaller number of parameters.

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Section: Results and Discussionmentioning

confidence: 64%

Section: Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Palma

Queimada

Coutinho

2019

Ind. Eng. Chem. Res.

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“…4 Hydrate formation is a wellknown flow assurance problem in the oil and gas industry. 5,6 Hydrates can reduce output or completely damage a pipeline in extreme situations. Therefore, the industry scrutinizes the conditions of hydrate formation in pipelines and often uses hydrate inhibitors 7 to ensure no risk of hydrate formation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Salts, Impurities, and Low Water Contents in the Formation of Gas Hydrates in CO₂-Rich Streams

Queimada,

Zhang,

Pedrosa

et al. 2024

J. Chem. Eng. Data

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Carbon capture utilization and storage (CCUS) together with natural gas production from high CO 2 -containing reservoirs has raised attention to the formation of CO 2 -rich gas hydrates. These gas mixtures can contain impurities such as Ar, O 2 , N 2 , H 2 , NxOy, CO, H 2 S, SO 2 , or mercury, some of which are also hydrate formers or potential corrosion enhancers. This paper addresses the use of thermodynamic models to predict the phase behavior of CO 2 -rich streams. It starts from the overall binary phase equilibria of CO 2 with water. Then, gas hydrates and the effect of different impurities on the hydrate phase behavior are observed. Furthermore, the effect of salts on CO 2 solubility and the influence of inhibitors such as salts on CO 2 hydrate suppression are analyzed. For modeling hydrates, the solid solution theory of van der Waals and Platteeuw, as implemented by Parrish and Prausnitz, is used coupled with the Cubic-Plus-Association equation of state (CPA EoS) for representing the fluid phases. The influence of electrolytes on hydrate formation and CO 2 solubility in brines is modeled with an add-on electrolyte term based on the Debye−Huckel theory. The main objective of this Perspective is to consider all possible phase equilibria simultaneously, as in CCUS applications we cannot detach the different phase equilibria conditions. The results demonstrate that the selected models can accurately represent the phase behavior of CO 2 -rich streams and the effect of salts and impurities on gas hydrate formation.

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“…The SAFT-type EOS and CPA EOS have been widely used to model vaporliquid equilibrium of the CO 2 -H 2 O or CO 2 -brine systems [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. Furthermore, many studies tried to combine the SAFT-type EOS or CPA EOS with vdW-P model to calculate three-phase equilibrium of gas hydrates [43,[66][67][68][69][70][71][72][73][74][75].…”

Section: Introductionmentioning

confidence: 99%

An Accurate Model to Calculate CO2 Solubility in Pure Water and in Seawater at Hydrate–Liquid Water Two-Phase Equilibrium

Sun

Geng

et al. 2021

Minerals

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Understanding of CO2 hydrate–liquid water two-phase equilibrium is very important for CO2 storage in deep sea and in submarine sediments. This study proposed an accurate thermodynamic model to calculate CO2 solubility in pure water and in seawater at hydrate–liquid water equilibrium (HLWE). The van der Waals–Platteeuw model coupling with angle-dependent ab initio intermolecular potentials was used to calculate the chemical potential of hydrate phase. Two methods were used to describe the aqueous phase. One is using the Pitzer model to calculate the activity of water and using the Poynting correction to calculate the fugacity of CO2 dissolved in water. Another is using the Lennard–Jones-referenced Statistical Associating Fluid Theory (SAFT-LJ) equation of state (EOS) to calculate the activity of water and the fugacity of dissolved CO2. There are no parameters evaluated from experimental data of HLWE in this model. Comparison with experimental data indicates that this model can calculate CO2 solubility in pure water and in seawater at HLWE with high accuracy. This model predicts that CO2 solubility at HLWE increases with the increasing temperature, which agrees well with available experimental data. In regards to the pressure and salinity dependences of CO2 solubility at HLWE, there are some discrepancies among experimental data. This model predicts that CO2 solubility at HLWE decreases with the increasing pressure and salinity, which is consistent with most of experimental data sets. Compared to previous models, this model covers a wider range of pressure (up to 1000 bar) and is generally more accurate in CO2 solubility in aqueous solutions and in composition of hydrate phase. A computer program for the calculation of CO2 solubility in pure water and in seawater at hydrate–liquid water equilibrium can be obtained from the corresponding author via email.

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Modeling of Hydrate Dissociation Curves with a Modified Cubic-Plus-Association Equation of State

Cited by 6 publications

References 59 publications

Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Effect of Salts, Impurities, and Low Water Contents in the Formation of Gas Hydrates in CO₂-Rich Streams

An Accurate Model to Calculate CO2 Solubility in Pure Water and in Seawater at Hydrate–Liquid Water Two-Phase Equilibrium

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Modeling of Hydrate Dissociation Curves with a Modified Cubic-Plus-Association Equation of State

Cited by 6 publications

References 59 publications

Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Modeling Hydrate Dissociation Curves in the Presence of Hydrate Inhibitors with a Modified CPA EoS

Effect of Salts, Impurities, and Low Water Contents in the Formation of Gas Hydrates in CO2-Rich Streams

An Accurate Model to Calculate CO2 Solubility in Pure Water and in Seawater at Hydrate–Liquid Water Two-Phase Equilibrium

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Product

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Effect of Salts, Impurities, and Low Water Contents in the Formation of Gas Hydrates in CO₂-Rich Streams